Fig. 1
From: Controlling skin microbiome as a new bacteriotherapy for inflammatory skin diseases
Structure of the skin and microbiota. The skin is the outermost barrier that covers the entire body and provides habitats for the microbiota (viruses, bacteria, fungi, and mites). The skin consists of epidermis, dermis, and adipose tissue. The epidermis is divided into four layers: stratum basalis, stratum spinosum, stratum granulosum, and stratum corneum, from the basal side to the apical side. The dermis and adipose tissue contain skin appendages, such as sweat glands (eccrine and apocrine glands), hair follicles, hair shafts, sebaceous glands, and arrector pili muscles. Eccrine glands produce sweat and open directly onto the epidermal surface through the duct, whereas apocrine glands and sebaceous glands connect to the hair follicle. The skin microbiota colonizes both the surface and appendages, and its composition varies depending on the microenvironment